Generally, LAI of maize was lowest in 2007, highest in 2008 and intermediate in 2009. In 2007, LAI was higher under PM and PSM than under SM and CK during the early stages of maize development. LAI was significantly higher at the fourth and fifth sampling dates on PSM plots, compared with PM and CK plots. However, LAI was significantly higher on SM plots than those of other treatments at the fifth and sixth sampling dates, and reached peak values later than under other treatments. LAI was significantly lower at the last two sampling dates on CK plots than those of other treatments. In 2008 and 2009, the patterns of LAI variations were similar, LAI being consistently and significantly higher on PM and PSM plots than on SM and CK plots. However, at harvest time LAI was significantly lower on PM plots, compared with PSM plots.